Ferroelastic Domain Walls in Barium Titanate-Quantitative Phenomenological Model

Properties of ferroelectric domain walls corresponding to rotations of the spontaneous electric polarization by 90 or 180 degrees are investigated in the framework of material-specific generalized Ginzburg-Landau-Devonshire model involving long-range dipole-dipole interactions. Thickness and surface energy for these domainwalls in the tetragonal and the orthorhombic phases of BaTiO(3) are evaluated in the charge-free approximation using model parameters determined from independent experiments. Both types of domain walls occur spontaneously in domain pattern simulations, although in the orthorhombic phase the 180-degree domain walls are very rare. The simulated domain patterns and domain wall properties are discussed and the relation to the pronounced anisotropy of the gradient term is pointed out.